Gas generator



P. MAURICE EI'AL GAS GENERATOR Filed Aug. l, 1950 l `Fam. 29, 1957 FIG. 2

A27 36 2s so 'g1 Picre MAURICE Pal TAVERNIEF? ATTOFQN EYS znited States Patent O GAS GENERATOR Pierre Maurice, Sevran, and PaulTavernier, Vaujours, France, assignors to French State represented by the Ministry of National Defense Application August 1, 1950, Serial No. 176,976 Y Claims priority, application France August 3, 1949V claims. (c1. 1oz-39) Our invention relates to methods and means for producing gases under pressure and chiefly to such methods and means that are used for producing large 'amounts of gasunder pressure during comparatively short periods. This is the case in particular when it is desired to produce gases for injecting liquid into a rocket, for feeding turbines, for starting turbo-machines, for catapulting aerials or submarine machines, for atomizing liquid for various purposes, for the emergency feed of various arrangements etc.

It has already been proposed to use for the purposes disclosed hereinabove gases formed during exothermic reactions in particular through the combustion of a solid or liquid substance that may be simple or formed by mixing before its use or otherwise, and chiefly of gun powder.

In the particular embodiments of said method, diiculties are, however, met by reason of the extremely high temperature of formation of the gases that may reach 1800 to 2000 C.

Now, for the feeding of turbines the gases should not reach a temperature higher than about 800 to 900 VC.` For injection of certain liquids into a rocket, they should not rise beyond 200 to 250 C. etc.

It is, therefore, essential in practice to providein those cases for a cooling of the gases before use. Y

My invention has for its object to allow the execution of the cooling in a manner such that the temperature of the gases at the moment of their use may reach the desired predetermined value that should be practically independent of the localrconditions in which the actual gases are produced, such as the external temperature, the position of the machine on which the gases are produced, the acceleration to which said machine may be submitted etc.

Our invention has also for its object the cooling of gases underthe most advantageous conditions as far as energy is concerned', through the agency of comparatively simple, light, cheap, small bulk arrangements.V

For this purpose, ourinvention consists primarily in resorting to the high gas temperatures due to the original reaction in order to produce a physical, chemical or physico-chemical phenomenon which produces as a secondary reaction further gases that mix with the primary gases, said production of further gases leading, consequently, to the desired reduction in temperature of the whole mass of gases. A f

-In the case where the secondary reaction produces'a' lowering of temperature that is too considerable as concerns the object sought for, the low temperature gases obtained as described hereinabove, may beV admixed in accordance with our invention with other high temperature gases obtained through the primary reaction and that have not been used for the secondary reaction, the proportions of the mixture being adjusted in a manner such that said mixture may reachthe final temperature desired We may mention among the physico-chemical reactions that may be used as disclosed hereinabove, in accordance with our invention, the following: the decomposition of the hydrates of a compound adapted to crystallize with a large number of water molecules such as calcium or magnesium chloride or sodium phosphate. Such hydrates are decomposed, as a matter of fact, at a moderate temperature, whereas the anhydrous body is stable at a high temperature. The secondary gases formed are then constituted simply by steam; the evaporation and/ or decomposition through heat of a solid compound that may be partly or wholly dissociated into gases with an absorption of heat, said compound being constituted by :ammonium chloride, hydrated or non-hydrated oxalic acid, ammonium oxalate, ammonium acetate, urea, ammonium carbonate and the like; the evaporation of a liquid product, suchv as water, alcohol, formic acid and the like;'the release, under the action of heat, of gases or liquids absorbed by a substance such asV active carbon or the like.

In practice, the products that are adapted to provide the secondary reaction, are carried inside a cartridge communicating with the chamber inside which the high temperature gases are produced, the arrangement of said products being such in said cartridge, that the secondary reaction may be executed in a smooth manner.

Thus, when the substances intended for the production f secondary reactions are constituted by solid material, they may be used, in conformity with our invention, either directly in the shape of granular particles of suitable size and shape or else in the shape of a mass provided with channels or else they are dispersed inside a porous material such as Sponges, pumice stone, charcoal or the like.

When the substances appear, on the contrary, in the form of a liquid such as water, alcohol or the like, they may be transformed into a solid form through the addition of some gelatinizing material and/or through absorption by a porous material.

In this latter case, the material thus assuming a solid form, may contain dissolved gases or solid compounds of the kind referred to hereinabove and adapted to produce gases `under the action` of heat.

It is also possible to provide for a combination of the different reactions mentioned hereinabove through mixtures of various substances referred to.

Further objects and features of our invention will appear in the reading of the following description, reference being made to accompanying drawings, illustrating by way of example and by no means ina limiting sense, two preferred embodiments of our invention. In said drawings:

Fig. 1 isa cross-sectional view of an arrangement for producing gases that are to serve for ejecting liquids into a. rocket, said gases being produced under a'pressure of 50 kg. per sq. cm. at a temperature of about 180 C., the gas output being equal to about 6 litres per second during l0 seconds.

Fig. 2 is a cross-sectional diagram illustrating an arrangement for producing gases at a temperature of about 750 C. for feeding a turbine.

Fig. 3 is a cross-section, on a larger scale, of the main parts forming the said arrangement.

In Fig. l, 1 designates a casing of a light metal such as an aluminum alloy adapted to contain the gas-producing means. This casing is closed a-t its front end by a cover 2 that is secured through bolts, 3 with the interposition of packings 4. 5 designates the outlet pipe carried by the cover 2 and serving for the outlet of the gases.

Inside the casing 1 is arranged a heat-insulating lining 6 constituted by a sheet of asbestos impregnated with: rubber. At the rear 0f the casing 1 is located a block ofpowder 7 the combustion of which is to produce gases under pressure at a high temperature. This block of powder may have a nitroglycerin base and assume the following composition:

This block is lined on itslateral and rear surfaces by an inhibitor varnish layer'S 'that is to'isolatef i t with reference tothe casing 1. Said varnish ve ts'tlie 'combustion of the powder from reachingfthe'surfacescoated thereby so that thepowder may burnfohlythrugh its ucoated front surface '9.' Infront o f saidsrface 9 is arranged a centering rnemt tojnstituted by af plu-j ralit'yfof steel arrn's'connectedpriplierally by'faiannulr element 11fandtheinner'e'r`1ds of which1 are rigidwitlr'a` tube 1 2V eXte'n-dingto'th'e fr o r`t'eid o tfjth'e casing'wh'ere' it'isscured'to'a plate 1 3 p 'd witli'op`e'r'1i1`fig's-1'4f Inside 'the'tube 12 is aria g'ed'a' block of powder 15 assuming a tubular 4shape'ad"tle corrposit'ioi'f which is the vsame as that of the block 7. Said blc1 is"not coated with Avarnish ahdeonsqetly'maybri over the wnp1e extent of its ote'tlgsufacfe: Itsfrntend is associated with a sn'talr igniting Hagi 16 co"nst ted'liy' afew gramsjof Vgunpowder adaptezl'to b'efign1ted`in'- its turn byV anelect'ric ignitei .17" coniieted with` tiniiiials 1 8 carried by tlie cover-2. 'fli "iitering member' 1'0 is coveredbyaj metal Screen 19`imp're`giiatedwith v(zellulose acetate while the, grating 13 is associated with a furtherY metal screen zo of the sameV type also impreg'i nated with cellulose acetate. Y

Inside the tubular space delined between the inner wall of' th e casing lining 6 an`d the outeiwall ofthe tube 12 on one hand and between the screens 19fa'nd 20 on the other hand, i s inserted a cooling charge' 21 constituted by charcoalimpregnated withA calcium chloride saturated with water. It should be remarked thatthe screen 19 is spaced withjrefer'ence to the wall 9; of the powder block 7 by' an empty space wherein the gases are allowed to evolve as soon as they pass out of the s 'aid block 7.

'The operation of the above arrangement is as follows:

When the ignition bag is' ignited through Vthe passage of anV electric current at 17 th'e surface of theauXiliary powder block 15 burns rapidly and the combustion is' propagated throughout theblockl The pressure rises rapidly until' it reaches the figure of 50 kglper so. 'cn-i. reguired, by reason of theY- combustion of this' audliaryl b10k, afterwhich normrp'mductiett of gases is nsufed throughthe mainf block 7 th e ignition of which is'fprofpressure of j the g'ses rises tllus .and as'said gases cannotpass out of the r'e'a'r' of tl cas' "gQefr'i'c'lo the charge d5 that remains closed, the gases their wy http thenambet 21asdisdosedhereinafter.

iAttn@ mqmntjdf the rise in pressure, the-` 'ctteof' cellulose` laid on the screens 19 and 20 tears open and allowsthe' gases vto passV through the cooling charge 21.l Said gases dehydrateV gradually the entire cooling charge o fncharcoal and pass out of thearrangement at a temperatureof l8 0 C. withjasaturating' amount of steam. As the 'gases are issuing t s tet'ttpetatute f 180 C., t l: le ot1 te r easing doesnotifi'sk b ngs'iiliittd to any exaggerated temperatut'eand 'it may' ns'qetly Bina'de as stated of alight alloy.

The' arrangement illustrated in Figs. 2 and 3 is'int'ended for the feeding of a turbine of 150 H..P. for one minutey with gases at a temperature'of about 750or C. Said arrangement isc'onstitut'ed by an outer casing 22 of duralumin assuming the shape of a cylinder having a cover 23 the fr ont end ofwhich 2 4 isoge'e-shaped. :Atthe vend of said t ermina1 ogee there is provided a-prt Z'nside which is fitted Va pipe` 26 for the exhaust'of thegass.

duced immediately upent'gnttin or the auxiliary '516er Inside the outer casing 22 is housed a steel casingconstituted by two elements arranged endwise, 27 and 28, the outer diameter of which is less thanthe inner diameter of the casing 22 so as to provide annular clearances 29 and 30 therebetween. The centering of the inner casing 27, 28 insidev the outer casing 22 is provided through any suitable centering means that is not illustrated, such as Welded ribs.- The'element 27 of the inner casing isadaptedvto receive the cylindrical -powderr block 31. The periphery of .this'block is coated withan inhibitor varnish 32 while its transverse surfaces"-33"`and 34 are free. To the rear of said latter surface 34.is located, as in thecase of'Fig. l,` acentering member 35 0n which a metal screen 36 bears,- that is coatedjwith cellulose acetate and that carries, furthermore, a tube 37 similar to the tube 12 of "Fig, land adapted to contain a tubular block of powder 38, similar to the block 15 of Fig. l.

Inside the casing' 28"? and* to therearof the' screen 3'6,'islh`ous`ed the co'oliiigchaig`e39"constitutedby'chan coal, impregnated withcalcium jchlo'ride lsaturate'til"with water.'v ,This charge is heldatits rear end' byfa'f'inetal screen40 coated with afce-tateofcellulosesimilar-tothe screen 20ct-the arrangement of Fig.- l; saidscr'eenbear rear closure 23 and is separated therefrom by a'spacingl` onl .one handu for igniting theI block of powder 38 and consequently the surface 34 of the block 31 andon 'the other hand; for igniting thesu rface" 3 3 of the blOCkISl.

The-front of the steel vtubeI or rsheath 27 ends'under the form 'of-lan" ogee 46 positioned at adistance :to therearof the above mentioned ogee 24 and insidesame, the outer wall "offsaid ogee 46 being; coated with Aani'nhibiting varnish'4'7. Furthermore, thei'nsideof the ogee 24"`arranged inthe vicinity of the openingZS 'is also coatedwith an inhibitor varnish 49.v

Theabove described arrangfen'ient operates as follows:

The simultaneous ring through' electric means ofthe smallcartridges 44and 45 beingprlo'ceededwith; the latter ignite simultaneously'the blocli'38v andthe surfaces 33v and 3 4 of the 1510er 31. Y,

The'heat'produced by this' rapidembustion of the livl`oclc38 has for its result, as in the case of Fig. 1, `a rise ofthe ypressure and temperature inside the charge39; The normal rate of smooth burning of the p owderis ensuredv throughl the'lc'ombustion of the powder block 31 through its surface 34.

At the' 'moment at which the pressure v'begins 'to rise, te 'cellulose coatdl on v the v screens f 316 an; t vnd provid s a passage frth vr'ornbu'stiforft"'gases issuing from thesurfalc'e 34 of the powder block 31. s thesegases pass through the cooling 'charge lalidprodce secondary Agases inside said charge, the temperaturefof the combustion gases that was originally'equal'to l8'00" is lowered downto about C. The `gses vescape through the' gr'ating'll into lthe space 4 3 andl 'swepfover the biotto ,oftheouterc'over after' which they w'bck vet `the 'inner wsu f said easing tnteghfthe openennulanspaces 30 a r1d 29 until they rcachfthe 'end'. of 46. At this latter' pontthef gases' nix'witttfutter' ses "produced by thec'ombustinof the surface 33 of the powder block, said gases being substantiallyi'ata temperature of l800 C, As a consequence of this mixirji'g theav'erage temperatureof the gases passing 'out of the port26 is equal to about 750 C., i. e. the'tenperature that isldesirable vfor the feeding'of a turbine of which is less than 200 C. whereby it is possible or said` easing to be made without any `drawbackof a light alloy as disclosed hereinabove. n l f ,The above described arrangement shows the advantage of operating without any moving mechanical means while assuming a cylindrical symmetry that provides for a regular distribution of the temperatures and of the stresses.

In the arrangement disclosed, the operation is ensured by mixing the gases produced by the combustion of both surfaces of`a same block of powder, the gases produced by one surface being cooled through the passage through a cooling charge and thenafter mixed with the hot gases from the other surface.

.It is alsol possible, according to our invention, to pr vide for the simultaneous combustion of two different powder blocks burning each through only one surface, the gases produced `throughthe combustion of one of the blocks being mixed with those produced through the combustion of the other block, afterl the latter has passed througha cooling charge. However, the use of a single chargeV burning throughout two opposed surfaces, leads obviousl'yto a combustion beginning on both surfaces and coming simultaneously to an end, which is preferable.

i. Furthermore, insteadof providing for an Vaverage'final temperature of `750 C, and when it is desired to obtain a higher or a lower final temperature, itis` suicient to produce-a smaller or greater amountof Vcool gases `with reference to the amount of uncooled gases. This result may be readily obtained in accordance with our invention through the use` of unequal combustion surface areas on the powder block or;blocks for the production of cooled or uncooled gases, `in other words, we may resort for instance tothe use of cylindrical powder blocks of. unequal cross-sectional areas. Obviously, numerous. modifications may be made to the arrangement described withoutun duly widening thescope of the present invention as de.- ned in accompanying claims.

.In particular, insteadof resorting to charcoal impregnated with water-saturated calcium chloride, experience has shown that it is possible to obtain highlyinteresting results through the use of ammonium bicarbonate assuming the shape of one or more blocks obtained through compression with a slight percentage of agglomerating material, say 3% of parain for instance. It may be of advantage to use said charge in the form of a block having a Acontact surface with the gases that is constant throughout operation, a cylindrical block being axially perforated for instance for thispurpose.

What we claim is:

l." An arrangement for produing a propulsive stream of compressed gases ata high predetermined temperature, comprising an elongated tubular casing including a front ogee-shapedV portion with a central opening in the latter, adiaphragm adapted to open at raised temperature, extending at least over part of the cross-section of the casing, ay forwardly openchamber to the front .of said diaphragm the side wall of which detlnesan annular gap with the inner surface of the casing, a charge of explosive material held in said chamber, extending throughout its breadth and having a front surface lying behind the front opening of the chamber and a rear surface spaced with reference to the front of the diaphragm, a second diaphragm adapted to open at raised temperature, extending across a part of the cross-section at the Vrear end of the casing, a cylindrical wallconnecting the'two diaphragms to f orm a closed compartment therewith, and separated 'from the' innersiifa'ceof 'the' casing by a gap opening into the justzmentioned gap',a s'olid mass of porous dissociatable material is said closed compartment for evolving a large amount of gases at raised temperatures, and means for igniting the charge of explosive material to produce a first primary mass of gases passing outwardly rdirectly through r tl'iefront c apenings in the chamber and in the casing, and a second mass of primary gases between the rear surface of the charge and the first diaphragm that provides for the passage of said second mass of primary gas through the solid mass in the closed compartment to carry along with it the gases evolved therein through the open second diaphragm and back through the gap between the inner wall of the casing, the cylindrical wall of the compartment and the side wall of the chamber into the opening at the front of the casing. v

2. An arrangement for producing a `propulsive stream of compressed gases at a high predetermined temperature comprising an elongated tubular casing provided with an axial opening at its front end, an inner substantially cylindrical partition lying at a small distance fromv the inner wall of the casing throughout the extent thereof and opening in register with the opening in the casing and rthe rear end of which partition is open and leaves a clearance between it and the rear end of the casing, the cylin drical space defined inside the partition communicating freely beyond the rear end `of the partition with ther-an'- nular gap between said partition and the inner wall of 'the casing, two diaphragms extending respectively across the medial portion and the rear end of the cylindrical partition and adapted to open upon application of heat, said diaphragms defining a first compartment between them and a second compartment to the front of the front diaphragm, a mass of explosive material in the second compartment and having a front surface at a small distance behind the front opening of the wall and a rear surface at a small distance in front of the front diaphragm, means for igniting said charge to produce two masses of gases through combustion of said mass along its front and its rear surfaces respectively, and a mass of porous dissociatable material evolving a large amount of gases at'raised temperature and loca-ted in the first compartment, the said mass being dissociated by the heat evolved by the gases formed at the rear of the first compartment, to form. a secondary `stream of gases, said las-t stream .of gases admixed with the gases from the rear surface of the explosive charge, being adapted to pass out of the rear end of the cylindrical partition into t-he gap separating the inner wall of the casing from the partition and out of the casing with the mass of gases from the front sur face of the charge of explosive material.

3. An arrangement for producing a propulsive stream of compressed gases at a high predetermined temperature, comprising an elongated tubular casing, an outlet pipe at the rear end thereof, a diaphragm collapsing at raised temperature and extending across the casing, a charge of explosive material to the front of said diaphragm with a clearance between its rear surface and the front surface of the diaphragm, means for igniting said charge passing axially through the rear part of the casing and through the diaphragm into proximity with said charge, a partition surrounding said igniting means and leaving an opening at its fron-t end, a filling of porous solid dissociatable material evolving a large amount of gases when submitted to the heat of the gases evolved by the combustion of the charge and entering said filling upon collapse of the diaphragm heated'by said gases, a second diaphragm extending across the casing slightly to the front of the rear end thereof and forming a cover for the rear end of last mentioned dissociatable filling and adapted to collapse under the action of the heat produced by the stream of combustion gases .admixed with the gases evolved by the dissociatable material, said last mentioned stream passing beyond said second diaphragm, when collapsed, in'to the outlet pipe. f v

Y 4. An arrangement for producing a propulsive stream of compressed gases at a high predetermined temperature, comprising an elongated tubular casing, an outlet pipe 'at the rear end thereof, la diaphragm collapsing at raised temperature and extending across the casing, a charge of explosive material to the front of said diaphragm with a clearance between its rear surface and the front surface of the diaphragm, means for igniting said charge passing through the diaphragm into proximity with said charge, a partition surrounding said igniting means and y nv'ar'rarigie'rrie'n't "for p'rridu'cing a VAprop uls'ive'stream 'of comp Vs sedgas'c'es"at -ahigh predetermined temperacomprising av casing' containing k'tv vo' 'separate and t ma'ssesdeEriing betweenfthenia'gap and tcon- 's ted respectively 'byy purelyexplosiye 'material and by porous "solid'Y material; dissocia'table vat aliigh temperae; diaphragm extending throughout said gap and 1the )or partfof which is constituted by l:material adapted "to `decon i pose on applicationr Eof heat, an igniter asso- `e=ted Withthel fst mass, the, eases produ-,Ced ,bythe combustion i of the 'fi-rst mass b eing' adapted to impinge o he second ma'ss to Aevolve' gas'esout of the latter for aw ixture therewith, a diaphragm extending inside the casing beyond the secondmass with reference ltov the rst 'mass Aand Imade Vat' least partly of material `decompusable by the heat of the hot inixtureio'f gases produced 'behind itg `a nd an `pnt1 et for the mixture of 'gases beyondrsaid secondldiaphragm. `An arrangement Afor producing a' propulsive stream compressed lgases a't a highpredeterrnined temperature, comprising acas'in'g,l a mass lof purely explosive material f filling 'part of said casing, a massof porous solid noncollapsible heatresisting carrier material impregnated with a Vdissociatable substance adapted to evolve gases when heatedl said mass filling alsofpart of the casing, xthe `two`masses facing each other throughout substan- `f tially the entire cros's'i-section of the casing, an igniter adapted to'act onuthe Surface of the explosive mass 'facing'the heat-resisting mass, means separating Ythe cooperlatingsiiirface of thcexplosivejrnaterial andfof nthe porous mass'iahd adapted to collapsewhen fsbmittfedto the heat ofcombustion yof `the explosive material to allow at least partiof the gasesproduced byfsaid charge `to enter Vthe porous'fm'ass and dissociate Vthe]"substance imp'regnating lthefl' tter. and means whereby the mixture 'ofcombusti'ogs'e's y'and of gases formed through dissociation of said -substance passes out of the casing.

7"'A'n" arrangement 'for "producing a propulsive'stream of mpie'ssed "gase'sfj ata high predetermined `tempeature; comprising a easingsbdividd'intotwo juxtaposed c y rt"ir"1eritsa vcharge of purely 'explosive'material fadapted Ito produce a large volumeof primary gasesat va very high'temperature and contained in the lirst compartment," a" 1.'iorous` 4mass of solid material resisting the actinof the' hot primary gases, contained in thev second 'compartmenhjsaid Vporous mass extending substantially itliro`u-g`l1outl the cross-'section' of the casing facing the ifrge'in "said first Ycomp'artfirent,4igniting means `for the explosive charge adapted to act on said charge' atfapoint iegisteringwith" the porous"1iass, said porou's'mass comprising a substance 'adapted to form'upon dissociation by heat a large amount 'o f gases, a diaphragm separating 'the `two 'compartments land adapted to open through decomposition Fupon combustion 4of the 'explosive material in i the nfirst 'compartment to provide thereby forthe passage bf"`the"'gasesproduced by thesaidconibustion'into the 'second tconipa'ranern 'and for thee/elution of tneseendary gases through dissociation"'f 'thejdissociatable "s nbst'aceg'nd-an 'output-"enamel'eonnected'with Itnei second 'compartment and 'fad-spied to 'conveying' stream' 'of eemvb'rrs'tioirf-'gises' adniixed winrth'e-v gasesv "evolved Ebyrthe dissinstablefinaterial. Y

' `8. `An'arrangement 'for producing a `propulsive ""s` trem ofeompress'ed'gases at a'hign predetermined temperature, comprisingacasing' a'mass of purely'explosive material filling 'one'V end 'fof "said"easing; Ya. porous support "resisting the 'action 'of the `het' gases produced vby the `'explosive of said charge and filling the other endfo" the icasing'and leaving a `narrow transverse ;gapfbetwe'n itv and theexplosivechar'ge' a^sn=bstance *adapted* 'toV evolve large amounts ofgases ai "fa raised/temperature" and "incorporated in said support, amigniter associated witha point of the'explosve'charge facing the l"porous mas's,""an`d 'an outlet pipe openingintothejcasing' beyond the location of porous support with 'reference t-o theexplosive tcharge 'and ladapteld'to collect the' mixture of gasespodu'ce'd. Y'9. arrangement lfior 'producing a propulsiv stream of compressed 'gasesat ahigh predetermined temperature,

iconiprisi'ng afc'asing, 'an' explosive'charge filling "one"por ti-on"ofthe"casing, a porous 'support radapted 'to'resist theaction'of the explosive gases Yevolved by said charge, lling "another portion ofthe casing "and extending subf 'stantially throughout Athe cross-section of said vcasing and leavinga"gap"'between it and Athe explosive chargegj'ignite'rs'a'ssocate'd with a ypoint of said explosive charge hear tnesaidfgpzandwitn a point nofthe 'latter facing away fromthev said gap; 'a' Vdissociata'blel substance carried inthe p'resfof the 'porous 'support' and adapted to evolve when Heated a'large 'amount of gases, thc'gases' produced byfthec'ombilstiono'f the explosive charge being adapted to impinge `on i'the lporous suppor-Vto evolve gases'jout of the substance carried by"`the latter, an'outletfpipe beyond the location 'off'the explosive charge witnrefer enceto' the porous support and adapted 4to collecty the `combustion"ga-ses' evolved through the surface of the explosive charge facing" thefoutlet pipe and by-pa'ss means wherethrough the combustion' gases passing through the porous support andadmixed with the Vgases evolved by the clis'sociatable substance are fed in said outlet, pipe.

'10. Anarrangement'for Iproducing a propulsive stream ofcompressed gases at a high predetermined temperature comprising a casing,V aLtirst 'mass of explosive material mounted within said casing, a second mass of material mounted within said casing in spaced relation Ito said first'mass to denne a gap therebetween, said second mass comprising a p-orous'support carrying a substance adapted to evolve large amounts of gases at raised temperature', an auxiliary mass o f explosive material extending laxially from said= gap into said 'second mass, an igniter mounted within said' casing inoperative relationship ,withsaid auxiliary .'mass; '.means. Ifor. directingqgases producedl v by the combustion of sid'; rstma'ss lintoinipingementupon said second mass to evolvegasesfroni saidsecond m'a'ss for admixture with the gases produced by the combustion of said rst mass, and an outlet pipe extending through said casing for releasing gases from the interior of said casing.

`leerenc/es,*Cited in the le iofvthisv patentv "g'ffl Y. Y. j 931,135 1,187,779 Patten' June '20,

FOREIGN PATENTS 474,717 France Dec. 22, 19'121 734,519 France lAug. 1, 1932 445,101 'Italy Feb; 8,' 1949 

8. AN ARRANGEMENT FOR PRODUCING A PROPULSIVE STEAM OF COMPRESSED GASES AT A HIGH PREDETERMINED TEMPERATURE, COMPRISING A CASING, A MASS OF PURELY EXPLOSIVE MATERIAL FILLING ONE END OF SAID CASING, A POROUS SUPPORT RESISTING THE ACTION OF THE HOT GASES PRODUCED BY THE EXPLOSIVE OF SAID CHARGE AND FILLING THE OTHER END OF THE CASING AND LEAVING A NARROW TRANVERSE GAP BETWEEN IT AND THE EXPLOSIVE CHARGE, A SUBSTANCE ADAPTED TO EVOLVE LARGE AMOUNTS OF GASES AT A RAISED TEMPERATURE AND INCORPORATED IN SAID SUPPORT, AN IGNITER ASSOCIATED WITH A POINT OF THE EXPLOSIVE CHARGE FACING THE PORUS MASS, AND AN OUTLET PIPE OPENING INTO THE CASING BEYOND THE LOCATION OF POROUS SUPPORT WITH REFERENCE TO THE EXPLOSIVE CHARGE AND ADAPTED TO COLLECT THE MIXTURE OF GASES PRODUCED. 